This disclosure is generally directed to granular feed supplements for ruminant animals. In particular, this disclosure provides a granular feed supplement for a ruminant in which a physiologically active substance is stable in the rumen of a ruminant animal and is digested and absorbed in the abomasum and subsequent digestive tract. Also disclosed are a method of making and a method of using the granular feed supplement.
Ruminant animals are mammals of the suborder Ruminantia that have a stomach divided into four morphologically distinct compartments: the rumen, the reticulum, the omasum, and the abomasum. The rumen and the reticulum are derived from the terminal portion of the esophagus, and only the omasum and the abomasum are considered to be a genuine stomach. Bacteria present in the rumen enable ruminants to digest cellulosic materials such as grass. Conventional digestion occurs in the abomasum, sometimes called the “true stomach.” Well-known ruminants include cattle, sheep, and goats.
The rumen, which is essentially a continuous fermenter, supports a variety of micro-organisms under neutral conditions which attack and digest much of the ingested feedstuffs consumed by a ruminant as part of their normal life cycle. Ingested protein material is broken down in the rumen to soluble peptides and amino acids that are used as nutrients by the microorganisms. A stream of ingesta, rich in microbial cells, passes out of the rumen into the omasum. The function of the omasum is to separate liquids and solids. Much of the liquid reenters the rumen while the remainder of the material enters the abomasum. Digestion and absorption then proceed in the abomasum in a manner similar to that found in monogastrics. Enzymes secreted into the lumen of the abomasum digest much of the material, including the microbial cells. The digested microbial cells provide protein and amino acids to the ruminant.
The microbial action of the rumen has the great advantage of being able to convert many feed components which have no direct nutritive value for the host into products which can be assimilated and utilized by the host. For example, urea may be converted to microbial protein which subsequently may be digested and utilized by the host animal. Cellulose may be converted to a mixture of volatile fatty acids which can serve as a source of energy to the host.
Unfortunately, this microbial action also presents certain disadvantages. For instance, soluble proteins of high nutritive value may be broken down and digested in the rumen and in part resynthesized into microbial protein of lower nutritive value. Amino acids are also chemically changed by the rumen microorganisms, which convert amino acids to carbon dioxide, volatile fatty acids, and ammonia.
All proteins present in animals are constituted by combinations of more than 20 different amino acids. Among these, ten “essential” amino acids are not adequately synthesized in the animal body, and the animals must take them in. When essential amino acids are lacking in the ruminant diet the ruminant's health, milk production, etc., are all negatively affected.
It is common practice in ruminant production to supply biologically active substances in the daily diet of the animals in order to improve their conditions of health and their productive performance. Active substances of interest include amino acids, vitamins, enzymes, nutrients such as proteins and carbohydrates, probiotic micro-organisms, prebiotic foods, mineral salts, choline, etc. Some of these substances are already normally present in foods used for feeding animals. Sometimes the amount of essential active substances present in the diet may be insufficient or inadequate to cope with states of deficiency or situations of high productivity. Therefore, it is desirable to carefully formulate or supplement the daily diet of ruminant animals in order to address these concerns.
However, when physiologically active substances such as amino acids and proteins are orally fed, a substantial part of the substance (e.g., proteins, amino acids, etc.) are decomposed by microorganisms in the rumen, making it difficult or impossible for the animal to effectively utilize all of the administered proteins and amino acids contained in feed, etc. Thus, essential amino acids are destroyed and rendered unavailable for animal production. Animal production is limited by the supply of individual essential amino acids that escape, or bypass, the rumen intact and reach the lower gastrointestinal tract where they can be absorbed and become available for animal production.
Accordingly, it is important to pass the biologically active substances through the rumen without decomposition by microorganisms to allow the biologically active substances to be effectively digested and absorbed in the abomasum and subsequent digestive tract. Consequently, a great deal of effort has been expended towards providing a bioactive substance in a form which will pass through the rumen essentially unaltered, yet undergo disintegration and absorption in the abomasum.
There are numerous methodologies that are designed to increase the amount of a nutrient that passes through the rumen without being degraded by the rumen microflora, thereby delivering a larger portion of that nutrient to the lower gastrointestinal tract, including: heat and chemical treatment, encapsulation and coating, use of amino acid analogs, and polymeric compounds of amino acids.
For instance, it has been proposed to coat ruminant animal feed additives containing biologically active substances with protective substances, such as fatty acids, hardened animal oils, and hardened vegetable oils. However, particles coated with these fats and oils are stable not only in the rumen, but also in the abomasum and subsequent digestive tract, making the biologically active substances difficult to be released in the abomasum and subsequent digestive tract.
Another method proposed utilizes the difference in pH between the rumen and the abomasum by coating with a polymer that is insoluble in the environment of the rumen but is soluble in the strongly acidic abomasum. Such polymers include polyvinylpyrrolidone, polyamides, and celluloses that have been chemically modified. This solution has the drawback of a high production cost, combined with the fact that using synthetic polymers introduces non-physiological substances into the animals' diet. Such polymer coating products thus require FDA approval.
A few patents disclose coating biologically active substances with material that allegedly survives the rumen but degrades in the abomasum.
For example, U.S. Pat. No. 3,541,204 discloses hydrogenated vegetable and animal fats and waxes such as rice bran wax as coatings that survive the rumen but are disrupted in the intestinal tract.
U.S. Pat. No. 3,959,493 describes utilizing aliphatic fatty acids having at least 14 carbon atoms each. The fatty acids are applied as a coating to an individual nutrient. The fatty acids are said to be resistant to rumen degradation. The active agents then are delivered to the abomasum and/or intestine where the fatty acids are reduced in the post-ruminal environment.
U.S. Pat. No. 4,642,317 describes a process for supplying fatty acids to ruminants in the form of their calcium salts. However, the sole use of fatty acid salts as feed additives creates a distinctly disagreeable odor from the oxidation of the organic volatiles in the feed causing a reduction in feed intake and milk yield.
U.S. Pat. No. 4,713,245 discloses a rumen-surviving granule comprising a core of bioactive material, a coating substance stable at neutral pH (as found in the rumen) but dissolved or disintegrated at pH=3 (as found in the abomasum), and at least one other coating selected from the group consisting of fatty acids having at least 14 carbon atoms and waxes, animal fat, and vegetable fat having a melting point of 40° C. or higher.
U.S. Pat. No. 4,808,412 describes a rumen stable composition containing an active agent molecularly dissolved with a basic polymer. The active agent is delivered post-ruminally because the polymer is resistant to a pH of greater than about 5, but is soluble or swellable at a pH of less than about 3.5. In this type of dispersion, some of the active agent at and near the surface of the composition will be destroyed by the action of ruminal microbes because cracks or channels can occur on the surface, reducing the effectiveness of the protection.
U.S. Pat. No. 4,832,967 discloses a two-layer rumen-surviving coating for water-soluble bioactive substances. The resulting particulate is stable at pH at least as high as 5.5, and releases bioactive substance at pH of 3.5 or less. The coating medium comprises an inner first coating layer consisting of material sensitive to pH variations and an outer second coating layer consisting of a hydrophobic composition that must include inorganic filler if the bioactive core has not undergone a surface treatment (application of hydrophobic binder). This hydrophobic outer coating layer is provided with a texture that permits diffusion or penetration of the external liquid medium. The outer coating preferably contains a mixture of hydrophobic substances.
U.S. Pat. No. 4,876,097 discloses a coating composition that is stable at pH less than or equal to about 3.5. The coating comprises a film-forming, water-insoluble binder that contains a substance that controls hydrophilicity, and optionally a substance that is sensitive to pH. Both waxes (hydrophobic) and propylene glycol (water-soluble) are suitable for controlling the hydrophilic/hydrophobic balance. Controlling the hydrophilicity of the particle is said to limit release of the bioactive material in neutral or slightly acidic media, i.e., in the rumen. In very acidic media, i.e., the abomasum, pH-sensitive fillers are activated by the media, which diffuses slowly at a rate established by the hydrophilicity of the coating. The resulting dissolution or swelling of the pH-sensitive filler degrades the coating and releases the bioactive material.
U.S. Pat. No. 5,093,128 describes a beadlet nutrient coating that includes fats and calcium based products. Coated ruminant nutrients have the disadvantage of cracking or abrading either in handling or in being masticated by the animal.
U.S. Pat. No. 5,145,695 provides a method wherein a particular feed composition that delivers an improved balance of essential amino acids post-ruminally is fed to a cow.
U.S. Pat. No. 5,227,166 discloses a feed supplement for ruminants consisting of a coated biologically active substance, such as an amino acid, drug, or vitamin. The coating composition comprises lecithin, at least one inorganic substance which is stable in neutrality and soluble under acidic conditions, and at least one substance selected from the group consisting of straight-chain or branched-chain saturated or unsaturated monocarboxylic acids having 14 to 22 carbon atoms, salts thereof, hardened vegetable oils, hardened animal oils, and waxes.
U.S. Pat. No. 5,496,571 discloses a method of encapsulating choline to produce a rumen bypass supplement for ruminants. This type of encapsulation produces spherical particles having a core of choline surrounded by a shell of fat. Encapsulation is a relatively expensive manufacturing process. Furthermore, the high degree of saturation of the fat needed for solidification tends to reduce the digestibility of the choline.
U.S. Pat. No. 5,714,185 describes a scheme for treating protein substances with zein/formaldehyde to render the ingredients protected from rumen degradation. However, formaldehyde results in the destruction and reduced bioavailability of most essential amino acids. Broderick, G. A. et al., “Control of rate and extent of protein degradation,” Physiological Aspects of Digestion and Metabolism in Ruminants, Tsuda et al., eds., p. 541, 1991; Academic Press, London. Furthermore, the level of formaldehyde sometimes used is too high, creating health concerns associated with its carcinogenicity and has not been approved by the FDA for animal feed applications.
U.S. Pat. No. 5,807,594 describes a method of improving weight gain and feed efficiency in a ruminant by encapsulating a choline chloride composition in a rumen-protected carrier. Suitable encapsulating or coating materials for use in this invention include hydrogenated oils, mono- and di-glycerides, waxes, and seed fats.
U.S. Pat. No. 6,022,566 describes the addition of fat to a feed ration and then adding rumen protected encapsulated choline chloride in an amount proportional to the added fat. However, such coatings and encapsulations of choline chloride are subject to abrasion, cracking, and other abuses during transport and handling, thereby rendering the coatings permeable to rumen fluids and microorganisms that destroy the choline.
U.S. Pat. No. 6,229,031 describes a method for manufacturing feed supplements by converting lipids that are byproducts of the food and meat processing industries to their calcium salt form.
U.S. Pat. No. 6,242,013 describes a ruminally-protected high oleic material produced by roasting oilseeds at high temperatures to protect the fatty acids fed to ruminants. However, the roasting procedures require costly energy consumption.
U.S. Patent Application Publication No. 2002/0127259 indicates that coated ruminant nutrients are disadvantageous due to cracking or abrading either in handling or in being masticated by the animal.
Japanese Laid-Open Patent Publication No. 60-168351 proposes a method of dispersing a biologically active substance in a protective substance which comprises granulating a biologically active substance containing at least 20% by weight of calcium carbonate and at least 10% by weight of a substance selected from the group consisting of monocarboxylic acid, a hardened oil and fat.
Japanese Laid-Open Patent Publication No. 61-195653 proposes a process for dispersing a biologically active substance in coating materials composed of at least 10% by weight of a substance selected from the group consisting of a monocarboxylic acid, a hardened oil and fat, and at least 20% by weight to not more than 50% by weight of an insoluble salt of an acid which is more weakly acidic than hydrochloric acid.
Japanese Laid-Open Patent Publication No. 63-317053 describes a method that comprises coating a biologically active substance with a coating material containing the protective substance composed of a monocarboxylic acid, hardened oil, lecithin, and a glycerin fatty acid ester.
WO 96/08168 describes a ruminant feedstuff to improve milk yields in dairy cattle. The feedstuff is composed of a rumen-protected choline compound having a protective coating containing at least one fatty acid or fatty acid soap.
Watanabe et al. (K. Watanabe et al., “Effects of fat coated rumen bypass lysine and methionine on performance of dairy cows fed a diet deficient in lysine and methionine,” Animal Science Journal, 77:495-502, 2006) report that the present technology to produce rumen protected amino acids has been limited to methionine. Watanabe et al. further report on the significant challenges of developing a rumen protected lysine, due to its physical and chemical properties. Watanabe et al. also indicate that from an industrial point of view, it was only worthwhile establishing rumen protected technology with hydrogenated fat and/or minerals, which are already registered as feed ingredients. Watanabe et al. disclose the bioavailability of fat coated rumen protected L-lysine hydrochloride in lactating dairy cows and the effect of rumen protected L-lysine hydrochloride and rumen protected methionine on lactation performance of high-yielding dairy cows fed a silage-based practical diet. Watanabe et al. report that the intestinal availability of their fat coated rumen protected lysine was calculated to be 66.2%.
In view of the foregoing problems, the need still exists to provide a feed supplement that protects a biologically active substance stably in the rumen of a ruminant animal and yet allows the effective digestion and absorption in the abomasum and subsequent digestive tract of the active substance.